1. Field of the Invention
This invention relates to hue control for color video systems, and in particular but not exclusively to hue control for component digital video systems.
2. Description of the Prior Art
In composite video systems such as NTSC analog video systems, hue control or adjustment is effected relatively simply by variation of the phase of the encoding or decoding subcarrier relative to the reference subcarrier burst. Thus any changes in the color of the resulting video image arising from phase variations can be compensated by control of the phase of the encoding or decoding subcarrier. The hue or color content of the signal can accordingly be varied while the saturation will remain constant.
However, in other types of video systems, it is not possible to provide a hue control of this type. For example, in a component video system using separate color component signals, there is no subcarrier and thus it is not possible to adjust the encoding or decoding subcarrier phase. Also, in a composite digital video system, hue control cannot be carried out in as simple a manner as that described above in the context of composite analog video systems.